How Can Tomatoes Safely Overwinter? Key Growing Techniques Explained

As deep winter arrives, temperatures gradually drop, and overwintering tomatoes face the test of low temperatures. Tomatoes are warmth-loving crops, and their tolerance in cold environments is limited. When growing or raising seedlings of tomatoes in winter and spring or in deep winter, they suffer cold damage when encountering low temperatures or frost. How can tomatoes safely overwinter? Which growing techniques need to be mastered?

I. How can tomatoes safely overwinter? Which growing techniques need to be mastered?

1. Topdressing

Tomatoes have a relatively long growing period and high yields, with large and comprehensive nutritional needs. Therefore, we must control the proportion of nutrients in the fertilizer to ensure it contains the nutrients tomatoes need. Before planting, apply enough base fertilizer, and to ensure healthy tomato growth, topdressing must also be done well during the growing period; tomato topdressing is mainly applied in small amounts but frequently. During the tomato seedling stage, foliar fertilizer should be sprayed appropriately, once a week, for two rounds, and then a water-soluble fertilizer should be applied once at the 4-true-leaf stage. In addition, after the seedlings have recovered, that is, during the fruit expansion stage, topdressing should also be done in time to promote tomato growth and avoid nutritional deficiency.

2. Temperature

Winter temperatures are relatively low, and normally this is not suitable for tomato growth, but greenhouse cultivation can effectively control the temperature. Therefore, in winter cultivation, temperature is the primary management task. The temperature suitable for tomato growth is around 22°C. Also, in winter the temperature changes somewhat between morning and afternoon; for example, the morning temperature is around 25°C and must not exceed 33°C. In the afternoon it drops by about two degrees, and at night the lowest temperature must not fall below 15°C, keeping the day-night temperature difference at around 12°C. If the temperature is below 10°C, tomato growth will be affected; below 4°C growth stops, and in severe cases the whole plant suffers freeze damage.

3. Light

Tomatoes also have relatively high light requirements, and their yield is directly related to light duration. During cultivation, we should improve the airiness and light penetration of the orchard, remove side branches in time, and prune old leaves, which not only increases the plant's light-receiving area but also reduces nutrient consumption and promotes healthy fruit growth. After tomatoes enter the white-ripe stage, all leaves below the fruit cluster should be pruned off to promote light absorption and also effectively reduce the incidence of pests and diseases. If natural light duration is insufficient, artificial supplemental lighting should be carried out when necessary to prevent tomato growth from being hindered.

4. Watering

Tomatoes have very large water requirements. Someone specifically investigated this, and during the tomato fruit development stage, each plant needs to absorb at least 1 kg of water every day. Therefore, when growing them, we must pay attention to watering well to keep the soil moist; the watering method is small drip irrigation, watering when dry and stopping when wet. However, to avoid soil salinization, a heavy watering is needed about every 28 days to flush out excess salts from the soil. In winter, however, pay attention to the water temperature; the water temperature should be controlled at around 10°C. If the water temperature is below 8°C, a large number of hollow tomatoes will appear, reducing fruit quality.

II. Tomato Growing Precautions

1. There are major misunderstandings in fertilizing: base fertilizer is too heavy, nitrogen fertilizer is too much, and biological bacterial agents and organic fertilizer are too little, resulting in oversized tomato leaves, slow tomato fruit expansion, and no fruit sizing; low soil organic matter content causes severe gray mold in the lower part.

2. Ridges are too low or no ridges are made: this causes low ground temperature and high humidity, and tomato roots develop slowly in such an environment, or even develop root rot, with reduced yield in mild cases. In more serious cases, total crop loss occurs.

3. Improper pruning and leaf thinning: some plants have poor light penetration, while others are defoliated excessively, resulting in no leaves on the lower part and only fruits, poor leaf light penetration, nutrient diversion, insufficient power for fruit expansion, and susceptibility to gray mold in the lower part; excessive leaf removal at the bottom reduces the leaves' photosynthetic capacity, leading to slow fruit expansion and coloring.

4. Improper use of flower-dipping agents: under different seasons and different weather conditions, flower-dipping agents of different concentrations should be used, but if one takes the easy way out and uses the same concentration on cloudy and sunny days alike, it will lead to deformed fruit or exposed seeds, affecting commercial value and yield.

5. Field management: watering is sometimes too much and sometimes too little, ventilation is done arbitrarily, and temperature control is improper, causing some tomato plants to grow leggy, some leaves to wither and dry up, and some flowers and fruits to drop.